<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box1 {
            background-color: skyblue;
            width: 50px;
            height: 50px;
            position: fixed;
            top: 20px;
            left: 50%;
            margin-left: 600px;
        }

        .box2 {
            background-color: pink;
            width: 1200px;
            height: 1000px;
            margin: 0 auto;


        }
    </style>
</head>

<body>
    <div class="box1"></div>
    <div class="box2">啦啦啦</div>
</body>

</html>